A massive clean-up was underway yesterday in the French pilgrimage town of Lourdes, famed for its Catholic sanctuaries, after flash floods forced the evacuation of some 450 pilgrims.

The waters from days of non-stop rain in the region have begun to recede but the main places of worship remained closed to the public, as firefighters pumped out water from a grotto and several hotels.

The cave, where Catholics believe the Virgin Mary appeared to peasant girl Bernadette Soubirous in 1858, remained flooded yesterday, with debris such as bits of wood, candles and branches floating on the surface.

Thierry Castillo, the custodian of the sanctuaries, said: “There have been floods in the past but this one has caused the most damage in the last 30 years.”

It was a fresh blow for the sanctuaries, which had a million-euro hole in a €30-million budget last year due to lower donations as a result of the eurozone crisis.

“We have serious damages, which will run into hundreds of thousands of euros,” Castillo said.

Pope Benedict XVI evoked the flooding at a special Mass in the Vatican, saying: “Let us turn to the Virgin Mary with a thought for Lourdes, the victim of flash floods that have inundated the grotto.”

The national weather service yesterday lifted the “orange alert” for rain issued for the area, but left in place an “orange warning” for floods.

Several areas in the town were inundated on Saturday as the river Gave de Pau burst its banks.

Buses ferried guests from all the hotels in the lower town to a conference centre and a sports complex. Two campsites were evacuated and several roads closed .

The body supervising the sanctuaries said a hydro-electricity unit providing power to the shrines had been badly damaged, as well as two pedestrian walkways at the side of the river.

Many visitors voiced disappointment. “I hope I will be able to pray at the grotto before I leave,” said Laura Generini, a Florentine. Others were undaunted and said they would return in spring.